LF OS
This is the 5th(?) attempt at writing an operating system from scratch, where "attempt" means: starting from zero.
Development mainly happens on my Gitlab at https://praios.lf-net.org/littlefox/lf-os_amd64 - check it out!
Key difference to previous attempts
- amd64, why use i386 like everyone else when I did not even manage to get a working system there?
- uefi and custom loader, why use Grub like everyone else when I did not even ...... ^
- I'm actually able to program things now
- I actually became a good software developer in the meantime
- first attempt was even before finishing school
- there are some docs
- I thought about system design and even wrote some things down
- I don't write throw-away code or just paste tutorials right now
- maybe later in user space though
Design
This will be a microkernel providing the following inside the kernel
- base system initialization (CPU, physical memory, common bus systems)
- memory management for processes (virtual memory)
- inter-process communication facilities
- mostly via shared memory and message queues
- later also via helper userspace programs to make communication between processes A and B over an arbitrary channel between C and D, where A, B, C and D may run on different computers
- IPC between different computers will be transparent to processes in a later version
- service registry
- processes announce services (file system, block device, character device, ...)
- other processes need services
- ask kernel for process implementing service x
- IPC to process for service x
All drivers for special hardware (everything not attached to a common bus) are userspace programs that will be designed to recover after crashed. They can store a small amount of information in the kernel (like hard disk x is fully initialized, just read from address $y and port $x) and when they crash, they are just restarted.
Since IPC between processes running on different computers is planned to be transparent, it's actually possible to run a single instance of LF OS on a whole data center (or bigger, but latency).